<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>customElements.define</title>
</head>
<body>
  <fl-badge>
    <button>按钮</button>
  </fl-badge>

  <template>
    <div id="fl-badge-template">
      <div>
        <slot></slot>
        <span class="number">88</span>
      </div>
    </div>
    <style>
      .number {
        border: 1px solid blue;
        border-radius: 6px;
      }
    </style>
  </template>

  <script>
    class BadgeElement extends HTMLElement {
      constructor() {
        super();


      }
    }
    customElements.define('fl-badge', )
  </script>
</body>
</html>